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Search Results: 1 - 10 of 527 matches for " Kensuke Yamamura "
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Cannabinoids Facilitate the Swallowing Reflex Elicited by the Superior Laryngeal Nerve Stimulation in Rats
Rahman Md. Mostafeezur, Hossain Md. Zakir, Hanako Takatsuji, Yoshiaki Yamada, Kensuke Yamamura, Junichi Kitagawa
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0050703
Abstract: Cannabinoids have been reported to be involved in affecting various biological functions through binding with cannabinoid receptors type 1 (CB1) and 2 (CB2). The present study was designed to investigate whether swallowing, an essential component of feeding behavior, is modulated after the administration of cannabinoid. The swallowing reflex evoked by the repetitive electrical stimulation of the superior laryngeal nerve in rats was recorded before and after the administration of the cannabinoid receptor agonist, WIN 55-212-2 (WIN), with or without CB1 or CB2 antagonist. The onset latency of the first swallow and the time intervals between swallows were analyzed. The onset latency and the intervals between swallows were shorter after the intravenous administration of WIN, and the strength of effect of WIN was dose-dependent. Although the intravenous administration of CB1 antagonist prior to intravenous administration of WIN blocked the effect of WIN, the administration of CB2 antagonist did not block the effect of WIN. The microinjection of the CB1 receptor antagonist directly into the nucleus tractus solitarius (NTS) prior to intravenous administration of WIN also blocked the effect of WIN. Immunofluorescence histochemistry was conducted to assess the co-localization of CB1 receptor immunoreactivity to glutamic acid decarboxylase 67 (GAD67) or glutamate in the NTS. CB1 receptor was co-localized more with GAD67 than glutamate in the NTS. These findings suggest that cannabinoids facilitate the swallowing reflex via CB1 receptors. Cannabinoids may attenuate the tonic inhibitory effect of GABA (gamma-aminobuteric acid) neurons in the central pattern generator for swallowing.
Automated bone marrow analysis using the CD4000 automated haematology analyser
Ryousuke Yamamura,Takahisa Yamane,Masayuki Hino,Kensuke Ohta,Ki-Ryang Koh,Izumi Tsuda,Takayuki Takubo,Noriyuki Tatsumi
Journal of Analytical Methods in Chemistry , 2000, DOI: 10.1155/s1463924600000109
Abstract: At present, bone marrow analysis is performed microscopically, but is time consuming and labour intensive. No automated methods have been successfully applied to classification of bone marrows cells because automated blood cell analysers have been incapable of identifying erythroblasts. The present study was designed to evaluate automated analysis of bone marrow aspirates with the CELL-DYN 4000 (CD4000) haematology analyser, which enables automated determination of erythroblast counts in both the normal mode (haemolytic time; 11.5s) and the resistant RBC mode (34.0s). The percentages of subpopulations including lymphocytes, neutrophils and erythroblasts were obtained with the CD4000, and as a reference, differential counts by microscopic observation of May–Grünwald–Giesa-stained films of bone marrow aspirates were performed (n=98). Significant correlations (P < 0.01) between the results obtained with the two methods were observed for total nucleated cell count and lymphocytes, neutrophils, erythroblasts and myeloid/erythroid (M/E) ratio. However, there were biases in the average percentages of erythroblasts, lymphocytes and M/E ratio obtained using the normal mode with the CD4000 toward values lower than those obtained with the microscopic method. Using the RBC resistant mode with the CD4000, the average percentages of erythroblasts, lymphocytes and M/E ratio approximated those obtained with the microscopic method. In conclusion, the CD4000 in resistant RBC mode is more useful for analysis of bone marrow aspirates than is the normal mode, because the former better approximates the M/E ratio than the latter.
The effect of minocycline on the masticatory movements following the inferior alveolar nerve transection in freely moving rats
Rahman MD. Mostafeezur, Hossain MD. Zakir, Yoshiaki Yamada, Kensuke Yamamura, Koichi Iwata, Barry J. Sessle, Junichi Kitagawa
Molecular Pain , 2012, DOI: 10.1186/1744-8069-8-27
Abstract: The number of Iba1-immunoreactive (IR) cells both in prV and motV was significantly larger in IAN-X rats compared with sham rats on day 3 after IAN-X. The intraperitoneal (i.p.) administration of MC caused a significant reduction of the number of Iba1-IR cells both in prV and motV that was evident on day 14 after IAN-X. Furthermore, a significant reduction of the number of Iba1-IR cells could be observed in motV but not in prV after microinjection (m.i.) of MC into the motV of IAN-X rats. The rats also exhibited a significant decrease in the head-withdrawal threshold on the side ipsilateral to the IAN-X compared to the threshold before IAN-X and it lasted to day 14. In addition, IAN-X markedly affected the ability to rat to carry out mastication. The number of complete masticatory sequences was significantly decreased. Furthermore, the total masticatory sequence time and food preparatory (PP) period duration was significantly elongated in compared to sham rats. Although IAN-X significantly affected the total number of chewing cycles within the RC period of a masticatory sequence, it had no effect on the duration of the chewing cycles. On the other hand, systemic administration of MC (both i.p. and m.i.) in IAN-X rats significantly improved decreased head-withdrawal threshold and the impaired masticatory jaw movements.The present findings reveal that the strong modulation of masticatory jaw movements occurs following microglial cell activation after IAN-X, and the modulation recovers after inhibition of the microglial cell activation by MC, suggesting that microglial cell activation in the motV as well as in the prV has a pivotal role in modulating mastication following trigeminal nerve injury associated with orofacial neuropathic pain.
Electricity Generation System with Piezoelectric Element Using Acoustic Radiation Energy  [PDF]
Hiroyuki Moriyama, Yuta Yamamura
Journal of Power and Energy Engineering (JPEE) , 2018, DOI: 10.4236/jpee.2018.610001
Abstract: In this study, a circular plate that is installing a piezoelectric element at its center is adopted as energy-harvesting system and is subjected to a harmonic point force. Because this system cannot avoid the influence of its acoustic radiation, the influence is considered theoretically using the equation of plate motion taking into account its radiation impedance and is estimated by the electricity generation efficiency, which is derived from the ratio of the electric power in the electricity generation and the mechanical power supplied to the plate. As a result, the efficiency is suppressed by the acoustic radiation from the plate, so that the efficiencies are so different in whether to take into consideration the radiation impedance or not. Because those results are verified by the electricity generation experiment and radiation acoustic energy has a hopeful prospect for improving the performance of this system, mechanical-acoustic coupling is used to make the most of the acoustic energy. Therefore, a cylinder that has the above plates at both ends is also adopted as the electricity generation system and mechanical-acoustic coupling is caused between the plate vibrations and an internal sound field into the cylindrical enclosure by subjecting one side of each plate to a harmonic point force. Then, the effect of coupling is evaluated by comparing with the efficiencies in the electricity generation system of only plate. Specifically, because the radiation impedance increases with the plate thickness, i.e., with the natural frequency of the plate, it is demonstrated that the effect of coupling becomes remarkable with increasing the thickness on the electricity generation efficiency.
Osteoconductivity Control Based on the Chemical Properties of the Implant Surface  [PDF]
Kensuke Kuroda, Masazumi Okido
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2018, DOI: 10.4236/jbnb.2018.91003
Abstract: Metallic materials, such as Ti, Zr, Nb, Ta, and their alloys, and also stainless steels are widely attractive as osteoconductive materials in the dental and orthopedic fields. Ceramics and polymers are also commonly used as biomaterials. However, they do not have high osteoconductivity in their pure form, and surface coatings with bioactive substances, such as hydroxyapatite or TiO2, are needed before implantation into the bone. Many reports claim that the surface chemical properties of implants, in particular, hydrophilicity and hydrophobicity, strongly affect the biological reactions. However, the effect of surface properties on osteoconductivity is not clear. In this review, we focus on the relationship between the surface hydrophilicity of metallic implants and osteoconductivity using in vivo evaluation, and the control of the osteoconductivity is discussed from the viewpoint of protein adsorption in implants.
Development of numerically controlled local wet etching
Kazuya Yamamura
Science and Technology of Advanced Materials , 2007,
Abstract: Numerically controlled local wet etching (NC-LWE) has been developed as a novel noncontact subaperture deterministic figuring method for fabricating ultraprecision optics or for finishing functional materials. In this method, a localized wet etching area is formed using a combined nozzle that is constructed by coaxially arranging the supply part and the suction part of the etchant. The removal volume anywhere on the workpiece surface is determined by the convolution of the removal function and the dwelling time distribution of the nozzle. The machining properties of this method are insensitive to external disturbances, such as vibration or thermal deformation, because the removal process is performed under a noncontact condition.
The Yang-Mills gradient flow and lattice effective action
Ryo Yamamura
Physics , 2015,
Abstract: Recently, the Yang-Mills gradient flow is found to be a useful concept not only in lattice simulations but also in continuous field theories. Since its smearing property is similar to the Wilsoninan "block spin transformation", there might be deeper connection between them. In this work, we define the "effective action" which generates configurations at a finite flow time and derive the exact differential equation to investigate the flow time dependence of the action. Then Yang-Mills gradient flow can be regarded as the flow of the effective action. We also propose the flow time dependent gradient, where the differential equation becomes similar to the renormalization group equation. We discuss a possibility to regard the time evolution of the effective action as the Wilsonian renormalization group flow.
Expression of TRPV1 Channels after Nerve Injury Provides an Essential Delivery Tool for Neuropathic Pain Attenuation
Hossain Md. Zakir, Rahman Md. Mostafeezur, Akiko Suzuki, Suzuro Hitomi, Ikuko Suzuki, Takeyasu Maeda, Kenji Seo, Yoshiaki Yamada, Kensuke Yamamura, Shaya Lev, Alexander M. Binshtok, Koichi Iwata, Junichi Kitagawa
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0044023
Abstract: Increased expression of the transient receptor potential vanilloid 1 (TRPV1) channels, following nerve injury, may facilitate the entry of QX-314 into nociceptive neurons in order to achieve effective and selective pain relief. In this study we hypothesized that the level of QX-314/capsaicin (QX-CAP) - induced blockade of nocifensive behavior could be used as an indirect in-vivo measurement of functional expression of TRPV1 channels. We used the QX-CAP combination to monitor the functional expression of TRPV1 in regenerated neurons after inferior alveolar nerve (IAN) transection in rats. We evaluated the effect of this combination on pain threshold at different time points after IAN transection by analyzing the escape thresholds to mechanical stimulation of lateral mental skin. At 2 weeks after IAN transection, there was no QX-CAP mediated block of mechanical hyperalgesia, implying that there was no functional expression of TRPV1 channels. These results were confirmed immunohistochemically by staining of regenerated trigeminal ganglion (TG) neurons. This suggests that TRPV1 channel expression is an essential necessity for the QX-CAP mediated blockade. Furthermore, we show that 3 and 4 weeks after IAN transection, application of QX-CAP produced a gradual increase in escape threshold, which paralleled the increased levels of TRPV1 channels that were detected in regenerated TG neurons. Immunohistochemical analysis also revealed that non-myelinated neurons regenerated slowly compared to myelinated neurons following IAN transection. We also show that TRPV1 expression shifted towards myelinated neurons. Our findings suggest that nerve injury modulates the TRPV1 expression pattern in regenerated neurons and that the effectiveness of QX-CAP induced blockade depends on the availability of functional TRPV1 receptors in regenerated neurons. The results of this study also suggest that the QX-CAP based approach can be used as a new behavioral tool to detect dynamic changes in TRPV1 expression, in various pathological conditions.
Fundamental physics on natures of the macroscopic vacuum under high intense electromagnetic fields with accelerators
Kensuke Homma
Physics , 2009, DOI: 10.1063/1.3204556
Abstract: High intense electromagnetic fields can be unique probes to study natures of macroscopic vacua by themselves. Combining accelerators with the intense field can provide more fruitful probes which can neither be achieved by only intense fields nor only high energy accelerators. We will overview the natures of vacua which can be accessible via intense laser-laser and intense laser-electron interactions. In the case of the laser-laser interaction, we propose how to observe nonlinear QED effects and effects of new fields like light scalar and pseudo scalar fields which may contribute to a macroscopic nature of our universe such as dark energy. In the case of the laser-electron interaction, in addition to nonlinear QED effects, we can further discuss the nature of accelerating field in the vacuum where we can access physics related with event horizons such as Hawking-Unruh radiations. We will introduce a recent experimental trial to search for this kind of odd radiations.
Observation of W decay in 500 GeV p+p collisions at RHIC
Kensuke Okada
Physics , 2010,
Abstract: W boson production is observed in $\sqrt{s}=500$ GeV proton proton collisions at RHIC-PHENIX experiment. The single longitudinal spin asymmetry $A_L(\overrightarrow{p}p\rightarrow W^+X)$ is measured via decay positrons in the mid rapidity region. The asymmetry $-0.83\pm0.31\pm(11%$ scale uncertainty) is consistent with calculations from various polarized parton distribution functions.
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